Correct Option: D

Expansion of agricultural land took place on the largest scale in Gupta age. The degeneration of the Vaisya's (the third, or trader caste), which had begun earlier, intensified during this period. Beacuse of advanced agricultural techniques and developments in handicrafts, the condition of the Sudra's (the fourth, or menial caste) improved and there was no great difference between a poor Vaisya and a prosperous Sudra.